Just as a side note...
Regardless of correctness, "don't name your files with obnoxious names" is good advice if you want to avoid problems with others' software. "0" is kind of a corner case, but if you stick to alphanumerics, '-', and '_', you're less likely to have to fix other people's stuff. On the one hand, you're "technically correct" using all sorts of filenames. On the other hand, you're just asking for trouble.